; Copyright (c) 2009 Michael Streif
;
; Permission is hereby granted, free of charge, to any person obtaining a copy
; of this software and associated documentation files (the "Software"), to deal
; in the Software without restriction, including without limitation the rights
; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
; copies of the Software, and to permit persons to whom the Software is
; furnished to do so, subject to the following conditions:
;
; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
; THE SOFTWARE.


BITS 64

global start
extern kmain

STACKSIZE equ 0x4000

section .enter

start:
; transfer execution to higher half

	lgdt[rel pointer]

	mov rax, higherHalf
	jmp rax

higherHalf:

   mov rsp, stack           ;set up the stack

   call  kmain                       ;call kernel proper

   hlt                                ;halt machine should kernel return
   jmp $

section .data

gdt:
   dq 0

    ;code
   dq 0x00209A0000000000

   ;data
   dq 0x0020920000000000

   pointer:
   dw $-gdt-1
   dq gdt


section .bss
   resb 0x4000                     ;reserve 16k stack on a quadword boundary
   stack:

